Ok here goes. In a sense you a right however what guru sahib is speaking of is deeper than what it seems. Guru sahib is speaking of the dimensions of what akaal purakh manifests in and its shakti. Same way how guru sahib has done ustat of devi chandi mata and has used references of this shakti being displayed in many forms. nirgun and satgun being two forms the physical manifestation of akaal purakh has always been coming on earth space universe... from the starting and even before guru nanak dev ji. "jab jab hoth aristh apara tabh tabh deh dharat avtara." so taking this tuk in context akaal p[urakh has taken many forms where its shakti has been represented through ram, krishan, bhrama, chandi, kali, guru nanak dev ji etc. however the guru sahibs have been given a higher status than the devteh because they have concurred all the 5 chor and have shown simran being akaal purakhs pooja ( the ultimate and final source) without having mankind worship them. in dasam granth guru sahib confirms that befoire taking birth he did tapasiya that he became one with akaalpurak so no difference between akaal purakh and guru sahib, showing that the gurus jot is one with akaalpurakh and later on even says that if anyone calls him god will go to hell. again this may seem contradictive however its showing a point what guru sahib has made of what they are and is saying that the ultimate simran is only of akaalpurakh not visible form. understand this sort of stuff is deep very deep very very deep however its simple as well again contradiction however when looking at the dimensions its not. another example we say guru nanak we "manifestation" of god himself "roop rabh dah" however god him self (guru nanak) i the form of god and shakti of god in guru nanak is saying to do simran of akalpurakh so in a way it is god telling you what to do ... sorry if this is confusing and typed in a rubbish format however have tried to make it simple.